ClickHouse/dbms/include/DB/AggregateFunctions/AggregateFunctionsMinMaxAny.h

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#pragma once
#include <DB/IO/WriteHelpers.h>
#include <DB/IO/ReadHelpers.h>
#include <DB/Columns/ColumnVector.h>
#include <DB/Columns/ColumnString.h>
#include <DB/DataTypes/DataTypeAggregateFunction.h>
#include <DB/AggregateFunctions/IUnaryAggregateFunction.h>
namespace DB
{
/** Агрегатные функции, запоминающие одно какое-либо переданное значение.
* Например, min, max, any, anyLast.
*/
/// Для числовых значений.
template <typename T>
struct SingleValueDataFixed
{
using Self = SingleValueDataFixed<T>;
bool has_value = false; /// Надо запомнить, было ли передано хотя бы одно значение. Это нужно для AggregateFunctionIf.
T value;
bool has() const
{
return has_value;
}
void insertResultInto(IColumn & to) const
{
if (has())
static_cast<ColumnVector<T> &>(to).getData().push_back(value);
else
static_cast<ColumnVector<T> &>(to).insertDefault();
}
void write(WriteBuffer & buf, const IDataType & data_type) const
{
writeBinary(has(), buf);
if (has())
writeBinary(value, buf);
}
void read(ReadBuffer & buf, const IDataType & data_type)
{
readBinary(has_value, buf);
if (has())
readBinary(value, buf);
}
void change(const IColumn & column, size_t row_num)
{
has_value = true;
value = static_cast<const ColumnVector<T> &>(column).getData()[row_num];
}
void change(const Self & to)
{
has_value = true;
value = to.value;
}
bool changeFirstTime(const IColumn & column, size_t row_num)
{
if (!has())
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeFirstTime(const Self & to)
{
if (!has())
{
change(to);
return true;
}
else
return false;
}
bool changeIfLess(const IColumn & column, size_t row_num)
{
if (!has() || static_cast<const ColumnVector<T> &>(column).getData()[row_num] < value)
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeIfLess(const Self & to)
{
if (to.has() && (!has() || to.value < value))
{
change(to);
return true;
}
else
return false;
}
bool changeIfGreater(const IColumn & column, size_t row_num)
{
if (!has() || static_cast<const ColumnVector<T> &>(column).getData()[row_num] > value)
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeIfGreater(const Self & to)
{
if (to.has() && (!has() || to.value > value))
{
change(to);
return true;
}
else
return false;
}
bool isEqualTo(const Self & to) const
{
return has() && to.value == value;
}
bool isEqualTo(const IColumn & column, size_t row_num) const
{
return has() && static_cast<const ColumnVector<T> &>(column).getData()[row_num] == value;
}
};
/** Для строк. Короткие строки хранятся в самой структуре, а длинные выделяются отдельно.
* NOTE Могло бы подойти также для массивов чисел.
*/
struct __attribute__((__packed__, __aligned__(1))) SingleValueDataString
{
using Self = SingleValueDataString;
Int32 size = -1; /// -1 обозначает, что значения нет.
static constexpr Int32 AUTOMATIC_STORAGE_SIZE = 64;
static constexpr Int32 MAX_SMALL_STRING_SIZE = AUTOMATIC_STORAGE_SIZE - sizeof(size);
union __attribute__((__packed__, __aligned__(1)))
{
char small_data[MAX_SMALL_STRING_SIZE]; /// Включая завершающий ноль.
char * __attribute__((__packed__, __aligned__(1))) large_data;
};
~SingleValueDataString()
{
if (size > MAX_SMALL_STRING_SIZE)
free(large_data);
}
bool has() const
{
return size >= 0;
}
const char * getData() const
{
return size <= MAX_SMALL_STRING_SIZE ? small_data : large_data;
}
StringRef getStringRef() const
{
return StringRef(getData(), size);
}
void insertResultInto(IColumn & to) const
{
if (has())
static_cast<ColumnString &>(to).insertDataWithTerminatingZero(getData(), size);
else
static_cast<ColumnString &>(to).insertDefault();
}
void write(WriteBuffer & buf, const IDataType & data_type) const
{
writeBinary(size, buf);
if (has())
buf.write(getData(), size);
}
void read(ReadBuffer & buf, const IDataType & data_type)
{
Int32 rhs_size;
readBinary(rhs_size, buf);
if (rhs_size >= 0)
{
if (rhs_size <= MAX_SMALL_STRING_SIZE)
{
if (size > MAX_SMALL_STRING_SIZE)
free(large_data);
size = rhs_size;
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if (size > 0)
buf.read(small_data, size);
}
else
{
if (size < rhs_size)
{
if (size > MAX_SMALL_STRING_SIZE)
free(large_data);
large_data = reinterpret_cast<char *>(malloc(rhs_size));
}
size = rhs_size;
buf.read(large_data, size);
}
}
else
{
if (size > MAX_SMALL_STRING_SIZE)
free(large_data);
size = rhs_size;
}
}
void changeImpl(StringRef value)
{
Int32 value_size = value.size;
if (value_size <= MAX_SMALL_STRING_SIZE)
{
if (size > MAX_SMALL_STRING_SIZE)
free(large_data);
size = value_size;
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if (size > 0)
memcpy(small_data, value.data, size);
}
else
{
if (size < value_size)
{
if (size > MAX_SMALL_STRING_SIZE)
free(large_data);
large_data = reinterpret_cast<char *>(malloc(value.size));
}
size = value_size;
memcpy(large_data, value.data, size);
}
}
void change(const IColumn & column, size_t row_num)
{
changeImpl(static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num));
}
void change(const Self & to)
{
changeImpl(to.getStringRef());
}
bool changeFirstTime(const IColumn & column, size_t row_num)
{
if (!has())
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeFirstTime(const Self & to)
{
if (!has())
{
change(to);
return true;
}
else
return false;
}
bool changeIfLess(const IColumn & column, size_t row_num)
{
if (!has() || static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num) < getStringRef())
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeIfLess(const Self & to)
{
if (to.has() && (!has() || to.getStringRef() < getStringRef()))
{
change(to);
return true;
}
else
return false;
}
bool changeIfGreater(const IColumn & column, size_t row_num)
{
if (!has() || static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num) > getStringRef())
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeIfGreater(const Self & to)
{
if (to.has() && (!has() || to.getStringRef() > getStringRef()))
{
change(to);
return true;
}
else
return false;
}
bool isEqualTo(const Self & to) const
{
return has() && to.getStringRef() == getStringRef();
}
bool isEqualTo(const IColumn & column, size_t row_num) const
{
return has() && static_cast<const ColumnString &>(column).getDataAtWithTerminatingZero(row_num) == getStringRef();
}
};
static_assert(
sizeof(SingleValueDataString) == SingleValueDataString::AUTOMATIC_STORAGE_SIZE,
"Incorrect size of SingleValueDataString struct");
/// Для любых других типов значений.
struct SingleValueDataGeneric
{
using Self = SingleValueDataGeneric;
Field value;
bool has() const
{
return !value.isNull();
}
void insertResultInto(IColumn & to) const
{
if (has())
to.insert(value);
else
to.insertDefault();
}
void write(WriteBuffer & buf, const IDataType & data_type) const
{
if (!value.isNull())
{
writeBinary(true, buf);
data_type.serializeBinary(value, buf);
}
else
writeBinary(false, buf);
}
void read(ReadBuffer & buf, const IDataType & data_type)
{
bool is_not_null;
readBinary(is_not_null, buf);
if (is_not_null)
data_type.deserializeBinary(value, buf);
}
void change(const IColumn & column, size_t row_num)
{
column.get(row_num, value);
}
void change(const Self & to)
{
value = to.value;
}
bool changeFirstTime(const IColumn & column, size_t row_num)
{
if (!has())
{
change(column, row_num);
return true;
}
else
return false;
}
bool changeFirstTime(const Self & to)
{
if (!has())
{
change(to);
return true;
}
else
return false;
}
bool changeIfLess(const IColumn & column, size_t row_num)
{
if (!has())
{
change(column, row_num);
return true;
}
else
{
Field new_value;
column.get(row_num, new_value);
if (new_value < value)
{
value = new_value;
return true;
}
else
return false;
}
}
bool changeIfLess(const Self & to)
{
if (to.has() && (!has() || to.value < value))
{
change(to);
return true;
}
else
return false;
}
bool changeIfGreater(const IColumn & column, size_t row_num)
{
if (!has())
{
change(column, row_num);
return true;
}
else
{
Field new_value;
column.get(row_num, new_value);
if (new_value > value)
{
value = new_value;
return true;
}
else
return false;
}
}
bool changeIfGreater(const Self & to)
{
if (to.has() && (!has() || to.value > value))
{
change(to);
return true;
}
else
return false;
}
bool isEqualTo(const IColumn & column, size_t row_num) const
{
return has() && value == column[row_num];
}
bool isEqualTo(const Self & to) const
{
return has() && to.value == value;
}
};
/** То, чем отличаются друг от другая агрегатные функции min, max, any, anyLast
* (условием, при котором сохранённое значение заменяется на новое,
* а также, конечно, именем).
*/
template <typename Data>
struct AggregateFunctionMinData : Data
{
using Self = AggregateFunctionMinData<Data>;
bool changeIfBetter(const IColumn & column, size_t row_num) { return this->changeIfLess(column, row_num); }
bool changeIfBetter(const Self & to) { return this->changeIfLess(to); }
static const char * name() { return "min"; }
};
template <typename Data>
struct AggregateFunctionMaxData : Data
{
using Self = AggregateFunctionMaxData<Data>;
bool changeIfBetter(const IColumn & column, size_t row_num) { return this->changeIfGreater(column, row_num); }
bool changeIfBetter(const Self & to) { return this->changeIfGreater(to); }
static const char * name() { return "max"; }
};
template <typename Data>
struct AggregateFunctionAnyData : Data
{
using Self = AggregateFunctionAnyData<Data>;
bool changeIfBetter(const IColumn & column, size_t row_num) { return this->changeFirstTime(column, row_num); }
bool changeIfBetter(const Self & to) { return this->changeFirstTime(to); }
static const char * name() { return "any"; }
};
template <typename Data>
struct AggregateFunctionAnyLastData : Data
{
using Self = AggregateFunctionAnyLastData<Data>;
bool changeIfBetter(const IColumn & column, size_t row_num) { this->change(column, row_num); return true; }
bool changeIfBetter(const Self & to) { this->change(to); return true; }
static const char * name() { return "anyLast"; }
};
/** Implement 'heavy hitters' algorithm.
2016-06-28 18:00:04 +00:00
* Selects most frequent value if its frequency is more than 50% in each thread of execution.
* Otherwise, selects some arbitary value.
* http://www.cs.umd.edu/~samir/498/karp.pdf
*/
template <typename Data>
struct AggregateFunctionAnyHeavyData : Data
{
size_t counter = 0;
using Self = AggregateFunctionAnyHeavyData<Data>;
bool changeIfBetter(const IColumn & column, size_t row_num)
{
if (this->isEqualTo(column, row_num))
{
++counter;
}
else
{
if (counter == 0)
{
this->change(column, row_num);
return true;
}
else
--counter;
}
return false;
}
bool changeIfBetter(const Self & to)
{
if (this->isEqualTo(to))
{
counter += to.counter;
}
else
{
if (counter < to.counter)
{
this->change(to);
return true;
}
else
counter -= to.counter;
}
return false;
}
static const char * name() { return "anyHeavy"; }
};
template <typename Data>
class AggregateFunctionsSingleValue final : public IUnaryAggregateFunction<Data, AggregateFunctionsSingleValue<Data> >
{
private:
DataTypePtr type;
public:
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String getName() const override { return Data::name(); }
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DataTypePtr getReturnType() const override
{
return type;
}
void setArgument(const DataTypePtr & argument)
{
type = argument;
if (typeid_cast<const DataTypeAggregateFunction *>(type.get()))
throw Exception("Illegal type " + type->getName() + " of argument of aggregate function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
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void addImpl(AggregateDataPtr place, const IColumn & column, size_t row_num) const
{
this->data(place).changeIfBetter(column, row_num);
}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs) const override
{
this->data(place).changeIfBetter(this->data(rhs));
}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
{
this->data(place).write(buf, *type.get());
}
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void deserialize(AggregateDataPtr place, ReadBuffer & buf) const override
{
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this->data(place).read(buf, *type.get());
}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
{
this->data(place).insertResultInto(to);
}
};
}